Fuse ejector



Sept. 27, 1938. T. E. MCDOWELL ET AL 2,131,292

FUSE EJECTOR Filed April 19, 1937 fig Patented Sept. 27, 1938 UNITEDSTATES PATENT ()FFICE FUSE EJECTOR Jersey Application April 19, 1937,Serial No. 137,669

1 Claim.

The present invention relates to a fuse ejector construction for fusedplug.

The invention relates more particularly to expulsion fuse constructionand is concerned with devices utilizing removable fuses of the cartridgetype wherein the fuses may be readily removed and renewed without theuse of tools to separate the parts maintaining the fuses in electricallyconnected relationship.

The present invention will be described in connection with a separableconnector of the type disclosed in Thomas E. McDowell Patent No.2,015,953, dated October 1, 1935, although it is to be understood thatthe present invention is capable of use in other embodiments.

The present invention is useful in external electrical conductors, suchfor example, conductors utilized for operating electrically drivenportable tools and the like, connections to the electrical equipment ofrailway trains while at rest to supply power for the operation ofair-conditioning apparatus, charging the train batteries, as well asother purposes.

Electrical connectors for use in the relations mentioned must be smalland constructed to afford no projections which catch as the conductorsin which such connectors are applied, are dragged from place to place inservice, at the same time such connectors must be small as possible andyet capable of carrying proper current, and at the same time constructedto withstand the severe and rough treatment received in normal use.

An object of the present invention is to provide a fused plug in whichthe fuse means may be readily removed and replaced in minimum time andwithout the use of tools.

Another object of the present invention is to provide a fused plug inwhich the insulating means carrying the conductor elements and fusecomprises two separable parts each recessed to provide, when together,pockets for the fuses, and in one of which parts the fuses arefrictionally gripped for preventing accidental displacement of the fusesas the members are connected or separated, while the other of themembers is provided with means for automatically displacing or ejectingthe fuses from the recesses in this member and to move the said onemember away from the other member when the holding means are released,thereby making it unnecessary to use a tool to separate the members orto withdraw the fuses from said other member of the insulating means ofthe plug.

The above other and further objects of the present invention will beapparent from the following description and accompanying drawing.

The accompanying drawing illustrates a fused plug constructed inaccordance with the principles of the present invention, and the viewsthereof are as follows:

Figure 1 is a view, partially in elevation and partially in centralvertical section along line I l of Figure 2, through a fused plug whichconstitutes one part of a separable electrical connector.

Figure 2 is an end view of the plug of Figure 1, looking the right-handend of the same.

Figure 3 is end elevational view of the inner or rear end of theinsulating body.

Figure 4 is a view, partially in elevation and partially in centralvertical section, showing one of the insulating members moved away fromthe other by the action of one form of fuse expulsion means of thepresent invention, when the means for holding the two members togetherare released.

Figure 5 is an elevational view of one of the insulating memberscarrying pin contacts, and showing the same with fuses carried thereby,and the screws, for securing the two members together, withdrawn.

Figure 6 is an isometric View of one of the fuse contact membersutilized in the recesses or pockets of the insulating members of theplug.

Figure '7 is a fragmental sectional view of a portion of an insulatingbody showing a portion of a cartridge fuse and another form of expulsionmeans for ejecting the fuse.

The drawing Will now be explained.

The plug shown in Figure 1 includes an insulating body comprising twomembers I and 2 which are adapted to be connected together forestablishing electrical circuit relationship,through enclosed removablefuses.

Members I and 2 are cylindrical, and are connected together by means ofscrews or bolts 3, 4, and 5, carried by the one member 2. The one member2 is provided with axially extending apertures E for the bolts, whichapertures are equally spaced, circumferentially, within the cylindricalsurface of the member. The member is recessed at l to receive the headsof the screws when the same are threaded into the other member I. Inorder to receive the screws in threaded engagement the other member I isprovided with threaded bushings 8, as may be readily observed in Figurel.

The member I is provided with conductors 9 passing from the inner end ofthe member, which is the left-hand end as viewed in Figure 1, andterminating within recesses or pockets l formed in the member. Bottomedin the recesses or pockets l6 are contact-making cups II which areelectrically connected to the conductors 9. The outer ends of theconductors 9 are provided with clips 52 and binding screws l3 forconnecting conductor wires to the several conductors 9. In the inventionas herein illustrated, there are three of such conductors 9,constituting three poles of the plug, while the fourth pole constitutesan elongated conductor element M which passes through the member fromend to end, and is prevented from rotation in said member by means of apolygonally shaped integral portion l5 which engages a correspondinglyshaped recess in the front face of the member. The rear end of thisconductor M is provided with a clip l6 and a binding screw il Thus theillustrated plug is arranged as a four-pole plug. 4

The three poles of the plug, which are electrically connected with theseveral conductors 9, are protected by removable fuses A, applied asillustrated.

The insulating member 2 is provided with recesses or pockets 53, withthe same number and axial arrangement as the pockets or recesses H! inthe member l. Within a pocket 18 is a cupshaped contact member l9 towhich is connected a pin connector 20, the connector 20 being solderedor otherwise secured to the cup IS, the cup and pin connection 2i! beingapplied in the member 2 by inserting the same through the open end of arecess it, the outer end of the member 2 being suitably apertured as at2! for the pin connectors 29. The cup-shaped contact member is, one ofwhich is illustrated in Figure 6, is so constructed as to frictionallygrip and hold one end of an inserted fuse A. The fuses A of known form,are provided with metallic end members 22 and 23 for making theelectrical connection with the cups l9 and ll respectively.

Fused plugs, of the general character herein described, have been inuse. However, it has been demonstrated by experience that the fusedplugs of the present type of manufacture, when it is necessary to renewthe blown fuses, offer resistance to ready fuse renewal.

Where such fuses have been inserted in fused plugs between. cups in theinner member I, and other cups in the outer member 2, oftentimes thecups engage the fuses with such frictional force as to prevent removalof the outer member 2 by a pulling pressure applied by hand to one ofthe pin contacts All. In such event the workman, has employed pliers topull the member 2, which is disadvantageous, as the pliers damage theengaged pin contact 26. Even when the workman is successful in pullingout the outer insulating member 2, by means of pliers or other toolapplied to one of the pin contacts 20, some times the fuses haveremained frictionally held in the inner member I. When this occurs aworkman attempts by means of pliers or other tool to pull out the fuses.To accomplish fuse renewal, in the manner just described, requires muchmore time than is warranted and necessitating shutting down a connectedelectrical tool or machine beyond a desired amount, and at the same timedamaging some of the vital parts of the connector.

The present invention overcomes the above recited objections byproviding expulsion means within the pockets or recesses ll] of theinner member I, to automatically free or expel the fuses, as soon as theouter member 2 is separated from the inner member I.

The means illustrated in Figures 1 and 4 for accomplishing this purpose,comprises a coiled spring 24 inserted in a cup or stationary fuse clip II of the member I. There are, of course, as many of the springs 24employed as there are cups II in the member I. Preferably the springsare of substantially conical shape in elevation, with their basessoldered or otherwise secured to the bases of the cups to prevent lossof the springs, while the insulating member 2 is separated from theinsulating member I. It is to be understood, of course, that other typesof springs or equivalent resilient means may be utilized in lieu of thecoiled springs illustrated. The springs 24 are placed under compression,when the member 2 is connected to the member I, to connect the fuses Ain circuit connecting relationship between the conductors 9 and the pincontacts 20 and remain under compression as long as these members areconnected. Whenever a fuse blows, all that the workman or operator hasto do is to release the screws 3, 3, and 5 from threaded engagement withthe insulating member whereupon the springs 24 become effective to shiftor eject the fuses, from the position shown in Figure 1, to the positionshown in Figure 4, moving with the fuses the outer insulating member 2,thus loosening it, so that the operator or workman may remove the member2 by grasping one of the pins 20 with his fingers and separating themember 2 so that the blown fuse or fuses may be replaced. When the blownfuses have been replaced the member 2 with the fuses therein is appliedto the member l, and the two members fastened together in operativerelation, by the screws 3, 4, and 5, as shown in Fig ure 1.

The fused plug herein illustrated includes a casing or housing 25 whichreceives a portion of the inner or rear end of the member I, when theparts are assembled. The housing 25 has an integral neck 26, which ishollow and through which the conductor wires are passed for connectionto the conductors 9 and M. A strain-relief fitting, designated generallyat 21, is provided for purpose well understood.

Surrounding the housing 25 is a sleeve 28 which extends beyond theextremities of the pin contacts 20 and the contact 14. The sleeve ismounted on the housing 25 for limited rotative movement for use indisconnecting the plug member from a mating receptacle, such as thatappearing in Thomas E. McDowell Patent 2,015,953. The sleeve 28 isprovided with elongated, circumferentially extending slots 29 and 30,through which pass screws 3! and 32 respectively for preventingseparation of the sleeve from the housing. One or both of the screws 3!and 32, or a third one, if necessary, may extend into and engagesuitable recesses in the inner insulating member I for maintaining theinsulating members I and 2 fixed in the housing 25.

While the invention has been described herein in connection with a plugmember of a separable connector such as that shown in Thomas E. McDowellPatent 2,015,953, nevertheless the invention may be incorporated inother forms of electrical connectors. The invention, however, findsready use in connection with the form of plug described, for the reasonthat the plug is of minimum diameter to reduce its weight and size, forthe current carried by the conductors. Thus the limitation of size is anitem to be regarded in connection with the present invention. It may bereadily observed that the space offered by the open end of the sleeve 28is limited so that it would be far from easy to insert a pair of pliersto grasp one of the pin contacts to separate the insulating member 2from the insulating member I, were the fuses gripped by the cups I I ofthe member I, thus offering material resistance to separation of themembers. By means of the present invention, as soon as the bolts orscrews 3, 4, and are released from threaded engagement with the memberI, the springs 24 immediately eject the fuses A from the cups II to suchan extent, as to separate the member 2 from the member I, whereupon itis easy to withdraw the member 2 from within the sleeve 28 and replacethe blown fuses with others.

The provision of the contact member l4 which serves as a safety groundcircuit and can not be fused because of code requirements also serves toguide the two parts, when pushed together, to maintain the polarity ofthe pin contacts after the member 2 has been separated from the memberI, and the former is returnedto again efiect electrical connectionthrough the plug.

Figure 3 illustrates the rear end of the member I of the insulating bodywhere it may be observed that the heads of the several conductors areseparated one from another by means of partitions 33, formed as integralparts of the member I, so that there is no likelihood of short circuitsoccurring between any of the contacts of the plug members.

Referring to Figure 6, it will be observed that the cups, of which thisis an example, are formed with bases 34 and spaced side walls 35, 36which are curvilinear in plan, and which are connected to the bases 34by necks 31 of reduced circumferential extent. The side portions 35 and36 are formed with legs 38 which extend toward the bases 34, and whichmay be slightly bent, prior to application of the cups to the pockets orrecesses, to frictionally hold the cups in place in the pockets orrecesses and at the same time engage the metallic ends 22 of the fuseswith sufiicient frictional clamping engagement to normally retain thefuses in the member A, against accidental displacement.

The fuse ejector of the present invention may be used with any sort ofan insulating body, with or without an enclosing sleeve, such as thesleeve 28, as the two members I and 2, comprising the insulating body,may be constructed as herein described and the springs 24, or equivalentmeans, employed to eject or free similar ends of the fuses, when themembers are separated for fuse replacement.

In order to prevent accidental loss of the screws 3, 4, and 5, from themember 2, by falling out, due to gravity, when the latter is removedfrom engagement with the member, the outer ends of the aperture 6 may bethreaded; and the apertures inwardly of the threads may be slightlyenlarged, thus permitting lengthwise movement of the screws within theaperture and preventing removal of the screws unless unscrewed throughthe threaded ends 40 of the apertures.

The principle involved in the operation of the ejector shown in Figures1 and 4, covers a stationary fuse clip, such as a cup I I, and anindependent spring, such as a spring 24, for ejecting a fuse.

Another principle of operation is involved in the arrangement shown inFigure '7, i. e., utilizing a movable clip secured to the free end of aspring,

the clip constituting the contact member following the fuse out of itspocket or cavity in the insulating member I.

Referring to Figure 7, a spring 4I is secured to one end, by solderingor otherwise, to the inner end of a conductor terminal 42, that is, theend of the terminal making contact within a pocket or cavity ID. Securedto the free end of the spring 4 I, as by soldering or the like, is ashallow clip or cup 43, which receives one end of a cartridge fuse A incircuit making relation.

When this type of ejector is used, the springs M are compressed when themembers I and 2 are connected together by the screws, and remain undercompression so long as members I and 2 are connected. When a fuse has tobe removed, the springs free or expel the fuses A from the pockets orcavities I0 and at the same time displacing the outer insulating member2 to the position shown in Figure 4, so that the member 2 and itscarried fuses may be readily removed from the casing 28. During suchexpulsion of the fuses A by springs operating under the principledescribed, the clips or cups 43-the contact membersfollow the fuses tothe limit of spring travel.

The showing of Figure '7 is not one of limitation, but is exemplary ofanother form of expulsion means. Spring or other shapes and kind may besubstituted for the one specifically illustrated, so long as theprinciple of operation is retained, viz., causing the clip, or anyequivalent contact member to follow the fuse, when expelled by thespring, to the limit of spring travel.

The invention has been described herein more or less precisely as todetails, yet it is to be understood that the invention is not to belimited thereby, as changes may be made in the arrangement andproportion of parts, and equivalents may be substituted, withoutdeparting from the spirit and scope of the invention.

The invention is claimed as follows:

An electrical connector of the class described comprising a shell havingan open end to receive a mating connector; an insulating pin carryingbody within said shell enterable through said open end and bottomedwithin said shell with its outermost face spaced inwardly of said openend; said body comprising two members connected together with adjacentend faces in contact and at rightangles to the casing axis; screw meansavailable through said open end for securing said two mem bers togetherwithin said casing; male contact pins projecting outwardly of theoutermost face of said body with the pin extremities terminatinginwardly of the plane of said open end; said body members beingcounterbored through their adjacent faces to provide cartridge fusepockets; contact cups bottomed in said pockets and connected in circuitrelation; and repellant springs in the cups of the inner body memberarranged to connect the fuses in circuit relation and possessingsufficient strength to automatically push the fuses endwise out of thesaid cups and therewith move the outer body member axially of the shellwhen said screw means are relieved, thereby freeing the fuses from thecups of the inner member and enabling ready removal of the outer bodymember by digital prehension with the fuses still in the cups of saidouter member.

THOMAS E. McDOWELL. WILLIAM A. WULLE.

